The present invention relates to an ultrasonic diagnosis apparatus for measuring the elasticity of biological tissues by sending ultrasonic push pulses thereto.
There are known elasticity measuring techniques for measuring the elasticity of biological tissues by transmitting ultrasonic pulses of high sound pressure (push pulses) thereto from an ultrasonic probe (e.g., see Japanese Unexamined Patent Publication No. 2012-100997). A typical measuring technique that utilizes the push pulses involves using an echo signal of measuring ultrasonic pulses to detect a propagation velocity of shear waves generated by vibration of the biological tissue subject to the push pulses, the detected propagation velocity being used as the basis for calculating an elasticity coefficient of the biological tissue in question. Another elasticity measuring technique utilizing the push pulses is one which calculates position information about the biological tissue using the echo signal of measuring ultrasonic pulses, the position information being used to calculate a displacement of the biological tissue induced by transmission of the push pulses.
In some cases where the above-mentioned elasticity measuring techniques are applied, the same location of the tissue is measured a number of times for elasticity so that an average of such measurements is presented as the final measured value. In such cases, if the biological tissue is moved by respiration, the location being measured is shifted, which renders the measuring of the same location difficult. To avoid such difficulty, the test object is asked to stop breathing for measurement purposes. However, it is sometimes difficult for the test object to keep stopping his or her respiration.
The biological tissue may also be moved by heartbeats or by the test object's movement. Furthermore, the biological tissue may remain still but the position and angle of the ultrasonic probe may change during measurement, which also makes it difficult to obtain accurate measured values of the elasticity of the biological tissue.
On the basis of data about the measured values of the elasticity of the biological tissue of interest (elasticity data), there also are cases where a two-dimensional elasticity image of the biological tissue is displayed in colors reflecting the elasticity data. If the biological tissue is moved or the ultrasonic probe is shifted in such cases, the echo signal obtained from the tissue contains noise. Thus when the biological tissue is moved, accurate elasticity data cannot be obtained and the S/N ratio of the elasticity image above worsens.